This invention relates generally to agricultural planting equipment, commonly referred to as air seeders, and, more particularly, to a mechanism for coating an airborne stream of small granular items such as seed, with substances in liquid or powdered form.
Seed treatment devices are known in the agricultural industry, as is reflected in Applicant's co-pending U.S. patent application Ser. No. 08/794,884, filed Feb. 5, 1997, and entitled "Application of Coatings to Seeds, Etc.". This seed treating mechanism is positioned generally remotely of the tanks in which the seed to be treated is transported over the field. The seed treating unit receives the flow of seed from the air transport system, treats the seed in a cyclonic chamber and discharges the seed to the ground engaging units in the air flow to be planted into the ground.
Treatment of the seeds remotely of the transport tanks enables the operator to handle only untreated seed, such that no special precautions are necessary. The seed is coated with the desired treatment only immediately before being planted into the ground. One example of the treatment of seeds involves the coating of the seeds with treatment fluids such as inoculants or fungicides within a seed delivery stream between a seed storage tank and a ground-engaging tool.
Another aspect of the instant invention provides a convenient and efficient method of coating particles within the parameters of an air cart.
As used with respect to the instant invention, the term "treatment fluid" is intended to cover both liquid and flowable solid or powdered substances that are introduced to the untreated seed as a coating thereto. Such coating material can be in the form of insecticides, herbicides, trace elements, inoculants and fungicides. The term seed is used in reference to the discrete seed particles that are to be or have been coated; however, the term is intended to cover other types of particles that may benefit from coating using the disclosed inventions.
Known seeding implements, such as described in the aforementioned co-pending U.S. patent application Ser. No. 08/794,884, carry seeds from a storage facility, such as a tank, to a ground-depositing tool by means of a flow of air. The flow of air is typically generated by a fan or compressor that is mounted on the seeding implement. Seeding implements, generally termed air carts or air seeders, are known in the industry that consist of one or more tanks for holding seed and or fertilizer, an air source such as a fan, and a metering and manifold system for delivering particles from the tank into one or more air streams.
Typical known seed coating processes for coating seeds have generally been carried out on an in-factory basis. That is to say, machinery is provided in which, for example, seeds are mixed with a coating material in a fluidized bed arrangement. Because the coating process is carried out in-factory, it is a relatively easy matter to ensure good quality control, especially as regards the thickness of the coating, and as regards the evenness of the thickness, over the seed, and seed to seed. When the coating is factory-applied, inevitably a long time must elapse between the application of the coating and the insertion of the seed into the ground.
Generally, the factory-applied seed coating cannot include moisture, as moisture might cause the seeds to deteriorate or even to germinate, the former never being desirable and the latter not being desirable before being planted into the ground. Often, however, it would be advantageous if a moisture content could be included in the coating, especially if the moisture were applied immediately before being inserted into the ground as the moisture could facilitate germination of the seed.
Another known method of coating seed is the mixing of batches of seed with treatment fluid on the farm prior to placing the seed in the air cart tank. This system is inefficient and requires the operator/farmer to handle the coated seed in some manner. Seed coated in this manner must be used within a limited time frame of when it is coated, and thus coated-seed not planted within a given time frame becomes wasted. This translates to losses due to the costs of wasted seed and wasted treatment fluids. This method also requires cleanup of the air cart tanks and loading equipment after treated seed is handled.
For the system described in the aforementioned co-pending U.S. patent application Ser. No. 08/794,884, the primary goal is to provide a system for applying a desired coating to the seeds on the air seeder immediately prior to insertion into the ground, whereby the seeds are inserted in the ground only a second or two after being coated. As a result, only the required number of seeds are coated, moisture need not be excluded, and all in all a greater freedom of choice of coating substances becomes available. Furthermore, wet or sticky materials can be added to the list of possible coating substances.
An important requirement is that the seed be coated evenly, not only over the surface of each seed particle, but also from seed to seed. Accordingly, an important goal would be the application of the coating to the seeds without compromising evenness and controllability of the coating, even though the coating operation is done actually on the air seeder, and takes place even as the operation of seeding is being carried out.
Improvements to the seed treating mechanism described in the aforementioned co-pending U.S. patent application Ser. No. 08/794,884 are desired and are reflected in the instant patent application.